[Danny Richie]

Speakers are still burning in now and a complete report on how they sound will have to come from others. I am sure many will hear these soon enough.

I did offer some brief comments at the bottom of the page where all the data was uploaded.

There is new information there as well regraded what was changed.

Since the link is now all over the Internet anyway I figured I might as well make it easy for those who look for it to find it.

http://www.gr-research.com/vmps626r.htm

Here is a pic of the new networks that went into the pair.



Please limit all questions to technical, and specifics and away from subject nature.

Thanks all of you for your interest in this project.

[zybar]

Looks nice.

What was the total cost of all the mods (parts and labor)?

George

[Danny Richie]

Right now parts total comes to $160. per speaker for Alpha Core foil inductors, Sonicaps, and Mills resistors.

Using Axon caps, foil inductors and Links resistors the parts total per speaker comes in at less than $60. a speaker

I have not decided what I will charge for assembled networks yet. I really don't have time to assemble a lot of networks.

[JoshK]

I'd be willing to assemble networks for those here in the NYC area (yes just NYC, sorry) that want them.  For free of course, or for a CD at most, just for the expierence of it.

[BrunoB]

Please limit all questions to technical, and specifics and away from subject nature...

What is the sensivity of the speakers?

Thanks

Bruno

[Woodsea]

Danny,
If I upgrade my 626's my Large Ribbon Center will be pretty ticked off    
What are my options?
Thanks,
Eric

[azryan]

I'd like to know the sens. too. It seems like it'd be 3db higher at least from your re-porting?

That reporting makes the woofer roll off a bit steeper right? What's the before/after F3's?

You've added BH5 and new wire, fiberglass, braces., new back plate, new binding posts... Is 'all' of that part of the mod prices you've listed?

'If' those mod prices are only for the x-over parts, how much for the BH5, posts,etc.. and could you supply that wire ('cuz it'd be tough for each customer I'd think to get their hands on a 'little bit' of that wire).

And per your -xover redesign you do bypass the L-pads totally right?

If yes...would someone be able to use your new x-over and keep the L-pads in the path and not use your resistors (this is clearly an important feature for many owners).

Also... would there be a listening test planned where there'd be a stock vmps for comp. by others?
I'd really like to hear opinions vs. your Diluceos too if people were willing to hear them too (I assume little arm twisting would be needed).

[azryan]

crap- maybe my list of questions would be best moved to the other thread about common questions? sorry. Too many similar threads on this. (feel free to move it if you want Danny).

[Danny Richie]

What is the sensivity of the speakers?

Right at 86db.

If I upgrade my 626's my Large Ribbon Center will be pretty ticked off  
What are my options?

That is a good question.

Can you send me some info or direct me to some info on that speaker?

That reporting makes the woofer roll off a bit steeper right what are the before/after F3's?

Looking at the predicted responses I would say that before the F3 was about 70Hz. Now it held a -4db level for a while until it starting a new roll off at about 34Hz and hitting a -6db at around 29Hz or so.

Now it is -3db down in the 37Hz range where it falls quickly. There is a slight drop in output in the 50 to 100Hz region just due to the oversize box that can't be helped.

It is better now than it was though.

You've added BH5 and new wire, fiberglass, braces., new back plate, new binding posts... Is 'all' of that part of the mod prices you've listed?

No, I just listed the price for the parts.

A couple of sheets of BH-5 will cover the pair easily. Those are $48. a sheet.

Binding posts are not a must as the old ones could be re-used if you can get everything de-soldered from it.

Fiberglass insolation and braces can be added by the owner without difficulty.  

There is not much extra wire needed. I'd be glad to through that in for anyone ordering parts from us.

And per your -xover redesign you do bypass the L-pads totally right?

The old variable L-pads are now only used to fill a hole in the box. Trying to remove them made little sense.

If yes...would someone be able to use your new x-over and keep the L-pads in the path and not use your resistors (this is clearly an important feature for many owners).

Not recommended. The old variable L-pads were one of the most detrimental things to the sound quality of anything else in there.

Also... would there be a listening test planned where there'd be a stock vmps for comp. by others?
I'd really like to hear opinions vs. your Diluceos too if people were willing to hear them too (I assume little arm twisting would be needed).

I'd love for someone to come over with a stock pair right now to compare them so you guys could get the sonic report from someone besides me.

I will not be giving a comparison to my Diluceo's either. They are close in one way though for sure. They use almost identical tweeters and the top end does sound the same.

[BrunoB]

Danny does not mention that his "fix" includes inverting the polarity of the midrange driver relative to woofer and tweeter, which destroys the phase integrity of the system. ...

Danny,

are all the drivers in the new crossovers in phase?

Bruno

[Danny Richie]

You guys try not to make this into a multi forum back and forth debate please.

This is a good question though and I will reply.

are all the drivers in the new crossovers in phase?

There are two ways to alter the phase integrity of a speaker, electrically, and mechanically (or physically).

Crossover components create shifts one way and then another that cause phase shifts and can alter the time coherency of the signal.

Likewise driver offsets can be more forward or back from each other that also cause a delay in the signal.

See more info on this at the Meadowlark web site:

http://www.meadowlarkaudio.com/Dbench9.htm

They build true time coherent speakers.

The problem is that we don't hear only the one axis response. We hear the entire room response. The room response inserts time delays all over the place and alters what we hear even if the original signal was time coherent.

Brian is correct (kind of). The polarity of the woofer and tweeter have been reversed to compensate for the physical alignment of the drivers.

In other words delay one driver 180 degrees (polarity flip) to align it with the other driver that is mounted behind it in time physically.

Flip the polarity on the whole thing and the mids will see reverse polarity compared to the other two.

Some CD's are recorded with the polarity reversed too. The Gladiator sound track was done this way. Flipping the polarity of your speakers will give you a slightly different sound stage feel with some systems.

The importance of drivers being wired in phase is nullified if the drivers are not aligned physically anyway.

The 626R did not have the drivers physically aligned.

Likewise our A/V series speakers are all wired with the drivers in phase, but they are not physically aligned and are not time coherent either.

Make sense?

[DFaulds]

Danny,

Looks like you've done some great work on this upgrade, although I doubt I will ever get to hear it.  One question I have about the changes you've made is about the bass alignment.  It seems to me that perhaps Brian's original alignment with a shelved reponse below 100 Hz and a -6db point of 29Hz would work quite well in an actual room.  Wouldn't normal room gain elevate the bass levels and provide a sold low end, pretty much flat to 29Hz?

[Danny Richie]

It seems to me that perhaps Brian's original alignment with a shelved reponse below 100 Hz and a -6db point of 29Hz would work quite well in an actual room. Wouldn't normal room gain elevate the bass levels and provide a sold low end, pretty much flat to 29Hz?

In some rooms it could be possible that it would not sound bad that way. It will cause the woofer to appear a bit lose though as it is slightly unloaded tuned that low.

In our room it was thin and that thinness was also apparent in the lower vocals.

What was noted here in our room by the 626R owner was that our A/V-1 had a stronger bass output. The A/V-1 is a small stand mounted speaker with a 5.25" woofer.

[azryan]

Could we get Chris 'texasphile'  to post his impressions?

He seems to be the only one who can (other than Danny who said he won't -though I think he'd state a 100% honest opinion).

[Danny Richie]

He's coming over tomorrow.

[Rick Craig]

With the crossover point for the ribbon being questioned by Brian I was wondering what the Fs is for that ribbon? Do you have a raw curve of the driver's response without the filter? Impedance curve? That would verify who's correct.

[Danny Richie]

Thanks for the good question Rick,

I have now read the replies on the Audio Asylum and can't believe Brian is resorting to scaring people into thinking that my crossover design would damage a tweeter, plus threaten no warranty...

That is sad.

Here is the impedance response you asked for on the VMPS tweeter (no network).



As you can see an Fs of 250 Hz suggests that they can indeed easily handle covering the 1,700Hz to 40kHz range that Aurum Cantus states on their web site.

What is also interesting is Brian is claiming that these tweeters do not come from Aurum Cantus.

I have the Aurum Cantus tweeters here on hand and I can tell you that they look identical. Castings are all the same, machined parts are all the same and will interchange. The ribbon elements are the same. The face plates will interchange, etc.

Not only that but the response and impedance are the same.

See the Aurum Cantus G-2 impedance curve below.



Look familiar?

Seeing as how these tweeters are identical and that Aurum Cantus has patented this technology in this, I am guessing that they will be really interested in this knock off, if it really was one.

I have been told that they are still pursuing legal issues Fountek.

Then there is Andre at E-speakers that has a contract with Aurum Cantus as the only North American importer for there products. I wonder if he knows something? Either he is suppling them to Brian or Brian is buying them without Andre's knowledge.

This could get messy.

Suffice to say though that the tweeter can be played easily down to a crossover point of 2,500Hz.

See response curves of a Diluceo:



I have had zero failures.

The Criterion also shares this crossover point.

I have had zero failures with it to, except for damaged caused from the wind or pulling the speaker quickly from a sealed plastic bag.

Rick, did you ever doubt who was really correct?

[doug s.]

hmmm....  just when i get finished posting on the vmps forum how i can put the vmps' back on my short-list, cuz brian sez it does not use the aurum cantus tweeter, now i'm being told it in fact *does* use the same tweeter.     oh well...

doug s.

[Rick Craig]

hmmm....  just when i get finished posting on the vmps forum how i can put the vmps' back on my short-list, cuz brian sez it does not use the aurum cantus tweeter, now i'm being told it in fact *does* use the same tweeter.     oh well...

doug s.

I've seen variations on this type of tweeter from four different manufacturers so it's very possible that it isn't made by Aurum Cantus; however, I have measured the G2/G2si and these curves are almost identical.

[DFaulds]

Danny, thanks for the thorough and complete answer to Rick's question, as well as addressing Brian's statements regarding the ribbon tweeter.  While I beleive all of your statements, and trust your measurements, it should be pointed out that it is very reasonable for Brian to void the warranty and not support one of his products that has had some major surgery, such as you have performed.